The present invention relates to a pager terminal, and more particularly to a pager terminal having a missing massage indicator for informing a user of message numbers appended to messages that are missed to be received.
There is a "serial message number service", which is offered as a supplementary service to users of a high grade pager system, such as the FLEX-TD (Time Diversity) system. In the serial message number service, a message number, which is appended serially to each call of a specified user of the pager system, is appended to each massage information. The message number is useful for transmitting message information reliably to the specified user. However, it is important to provide an effective measure to make use of the message number for detecting and indicating reception failure also on the side of the pager terminal receiving the message number.
As a prior art of a method for preventing reception failure in this type of pager system, there is a Japanese patent application entitled "Method for detecting reception failure of transmitted messages" and laid open as a Provisional Publication No. 119725/92.
In the prior art, the transmitting station transmits, periodically to each pager terminal, a serial message number information comprising information of the calling number, the date information, the serial message number at present time, and the identification information indicating that the message is the serial message number information, besides ordinary message information which is transmitted together with the calling number, the date information, a serial message number counted from the beginning of the date and the identification information indicating that the message information is an ordinary message information.
At each pager terminal receiving the message information, it is discriminated whether the received message information is the ordinary message information or the serial message number information. When it is the ordinary message information, an internal count number is incremented and stored with the date information. When it is the serial message number information, the serial message number of the information is compared with the internal count number for detecting whether there is any missing message or not to be informed to the user with an alarm through a speaker.
As above described, only when the serial message number information, which is transmitted periodically from the transmitting station for reporting the current serial message number, is received, the current serial message number is compared with the internal count number incremented at each reception of the ordinary message information, in the prior art, and an alarm is sounded through the speaker to report the reception failure to the user when the compared two numbers do not agree.
Therefore, the user is informed of an existence of a reception failure, but he cannot decide, at the instant, that which one of the messages is missed to be received. The missing message information might be an important information for the user.